Multiple source recording

ABSTRACT

A system and method are disclosed that accepts different types of signals from multiple sources and routes the signals to the appropriate devices for conversion or other processing so that each signal is in a common or desired format, such as the MPEG standard. The individual signal streams are packetized so that each signal stream carries identifying information associated with it originating signal source and then multiplexed onto a single digital transport stream for storage. Such a system allows overlapping signals of different types from multiple sources to be processed and stored in a single storage device. Each of the signals can then be subsequently retrieved for playback or display.

This is a continuation and claims the benefit of priority of U.S. patentapplication Ser. No. 09/519,799, filed Mar. 6, 2000, now U.S. Pat. No.6,704,493 and entitled “Multiple Source Recording,” which isincorporated by reference herein in its entirety.

BACKGROUND

1. Field of the Invention

This invention relates to recording and storing signals and, inparticular, to recording and storing signals from multiple sources.

2. Description of Related Art

Currently, there exists a large number of analog and digital signalsavailable for home use. Analog signals include conventional televisionsignals that are typically sent directly to a home television receivervia cable, satellite, or terrestrial transmissions using analogstandards such as NTSC, PAL, and SECAM. Other analog signals include RFsignals, audio signals, and data streams. More recently, signals (bothvideo and audio) are also being transmitted digitally, which have beenencoded according to the MPEG (Moving Pictures Experts Group) standard.

Home networking allows these signals from multiple sources to beconnected to and output from a single source, such as a television(monitor and speakers), so that consumers can receive a variety ofentertainment and information on their television sets. However, not allsignals are standardized in a common format, i.e., they are transmittedwith different formats, thereby requiring different types of receiversor devices to receive and process the various signals to an appropriateoutput format. These devices can include set-top boxes (STBs), videocassette recorders (VCRs), satellite dishes, and cable boxes forreceiving signals from transmission methods such as direct satelliteservice (DSS), microwave broadcast, cellular television (“wirelesscable”), and television delivered via digital telephone phone lines.Further, as home television systems become more advanced and the numberof signal sources that such systems can receive increases, situationsmay arise where signals from two or more sources are desired duringsimultaneous or overlapping time periods.

In these cases, different recording and storage devices are required foreach signal source. For example, an analog video cassette recorder (VCR)can be used for recording analog video/audio signals, a tape, CD, MD, orsolid state memory can be used for storing analog/digital audio anddata, and a memory card and hard disk drive (HDD) can be used forstoring and retrieving digital video, audio, and data. Thus, separateand differently formatted recording devices are needed to store andrecord one or more of the different signals simultaneously for laterretrieval. As the number of different signal sources continues toincrease, the number of separate recording and storage devices will alsoincrease, thereby increasing both the size and cost of the homenetworking system.

Therefore, it is desirable to provide a system for simultaneouslyrecording and storing signals from multiple sources that overcomes thedisadvantages discussed above associated with conventional systems.

SUMMARY

In accordance with an aspect of the invention, a system and method areprovided which allows simultaneous signals from various sources to beprocessed and stored for later retrieval and playback. Analog signalsand digital signals of various formats are input to a source interface.The source interface routes selected signals, via a selector device suchas a remote control, to appropriate devices for processing. Analogsignals are routed to an analog tuner/demodulator to demodulate the RFsignals down to IF signals. The IF signals are then transmitted to adecoder for converting the IF signals to a common analog format, such asNTSC, PAL, RGB, or YUV. The analog signals are then digitized using ananalog-to-digital converter. The sampling rate or frequency can beselected by the user or automatically selected based on the quality ofthe analog signals and the quality of the output display device. Oncethe analog signals have been converted to digital signals, the digitalsignals are sent to an encoder for time-compression (e.g., MPEGencoding) to reduce the bit rates. After encoding, the digital signalsare stored in a buffer.

Digital signals already in the desired format (e.g., MPEG) are routed toa demultiplexer to separate the digital stream into individual datastreams, such as video and audio. These digital streams are also storedin the buffer. Digital signals in a format different than the desiredformat are first converted to the desired format by a converter beforebeing transmitted to the buffer. Once all the signals from the varioussources are in a common desired digital format (e.g., MPEG), the signalstreams are sent to a packetizer for processing each signal stream intopackets for identification and later retrieval. Once the signals havebeen packetized, they are sent to a formatter, which multiplexes thesignals onto a single digital transport stream. The transport stream canthen be stored in a digital storage device to be accessed at a latertime. Thus, signals transmitted simultaneously or during overlappingtime periods from different sources can be stored and retrieved byaccessing specific packets within the stored transport stream. Thiseliminates the need for multiple decoders to receive and decode theincoming information.

The present invention will be more fully understood upon considerationof the detailed description below, taken together with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a system for recording multiple signalsources according to one embodiment of the present invention; and

FIG. 2 is an example of a portion of a transport stream of the presentinvention.

Use of the same reference symbols in different figures indicates similaror identical items.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with the present invention, selected analog signals fromanalog sources are demodulated, decoded to a common analog format, anddigitized and compressed to a desired digital format suitable forprocessing by an output device. Selected digital signals that are in thedesired digital format are demultiplexed to separate signal components(e.g., audio and video components) from the digital signal stream. Otherdigital signals not in the desired digital format are first converted tothe desired digital format. The resulting digital data streams are thenpacketized and combined into a single data digital transport stream forstorage and later retrieval. As a result, signals of different formatsfrom different sources can be simultaneously recorded and accessed forsubsequent use.

FIG. 1 shows a block diagram of a system 100 according to one embodimentof the invention. System 100 includes a source interface 105, a sourceselector 110 coupled to source interface 105, an analogdemodulator/tuner 115, a digital converter 120, and a demultiplexer 125each coupled to source interface 105 and source selector 110, a decoder130 coupled to demodulator 115, an analog to digital converter (ADC) 135coupled to decoder 130, a digital compression circuit or encoder 140coupled to ADC 135, a buffer 145 coupled to source selector 110, digitalconverter 120, demultiplexer 125, and encoder 140, a packetizer 150coupled to source selector 110 and buffer 145, a stream formatter 155coupled to packetizer 145, and a digital storage 160 coupled toformatter 155.

Source interface 105 accepts signals from multiple sources, e.g., analogvideo signals such as NTSC, PAL, and SECAM signals from VCRs, satellitereceivers, set-top boxes, cable boxes, and coaxial cables, analog audioand data signals from tuners and telephone lines, digital video andaudio signals such as MPEG, MPEG-2, and DirecTV™ signals from digitaltelevision sources, and digital data signals other inputs to sourceinterface 105 can include demodulated inputs for analog video/audio datavia phono connectors or multi S-terminals. Regardless of the signalsource, the signals input to source interface 105 have identifiers thatallow source interface 105 to select and route specific signals todesired destinations.

Source selector 110 selects which ones of the signals input to sourceinterface 105 are to be recorded, based on either user supplied inputsor predefined selection criteria. For example, source selector 110 couldbe a remote controller, in which the user selects the sources, theparticular channel for each source, the start and end time of eachchannel to be recorded, and any other suitable information. Sourceselector 110 can also select signals based on previous history, such aspro-selected favorites. In addition to selecting signals, sourceselector 110 also provides information or data to other blocks, such assampling rate for analog-to-digital conversion and insertion ofadditional data, such as title, time, and/or source associated with thesignal.

Once the desired analog and/or digital signals are selected, and at theappropriate time(s), the signals are routed by source interface 105 todemodulator 115, digital converter 120, and/or demultiplexer 125,depending on the type of signal. Analog signals are sent to analogdemodulator/tuner 115 to recover original information from the signal.Demodulator 115 demodulates the RF analog signal down to an IF signalfor input to decoder 130. The IF signal is then decoded to a commonanalog format, e.g., from a composite analog signal format such as NTSCof PAL to a component analog signal format such as RGB (Red, Green,Blue) or YUV (luminance signal (Y) and two color difference signals R-Y(U) and B-Y (V)), by decoder 130. Decoder 130 is an analog decoder andcan be a multi-standard device for NTSC/PAL or separate for SECAM. Atthis point, all the selected analog input signals are in a common analogformat.

ADC 135 then samples and converts each of the analog signals to adigital signal. For example, ADC 135 can be a standard 8 to 10 bitanalog-to-digital converter, which can have a variable samplingfrequency or rate, depending on the original signal source quality andthe desired output quality. The length (or time) of content stored isdirectly proportional to the number or samples (or frequency). Forexample, if the source is standard NTSC, sampling the analog signalabove approximately 4 to 5 MHz would be impractical since the quality ofthe original signal is below that indicated by the sampling rate.Similarly, if the display or signal output device is not capable ofdisplaying a high quality signal, such as a High Definition signal forHDTV, then sampling the analog signal at an accordingly high data ratewould be impractical as the resulting high quality data signal could notbe adequately displayed on the output device. In some embodiments, thesampling frequency is automatically selected based on the type of signalsource and output device. In other embodiments, the sampling frequencycan be manually selected by the user so that the user can choose betweentrade-offs of time and quality. For example, a high quality signal mighttypically be represented by 12 bits (8Y:4U:4V), but a user may select asampling rate so that the signal is represented by 6 bits (4Y:1U:1V).This results in a lower quality output signal, but allows for longerrecording times, similar to the differences between an SP and an LP (orSLP) recording mode.

After conversion to a digital signal, encoder 140 time compresses thedigital signals to reduce the bit rates, e.g., according to the MPEGstandard, MPEG-2, or other suitable standard. The resulting MPEG streamis then transmitted to buffer 145.

Digital signals that are already in the desired format, e.g., MPEGstandard, and have multiple signal components, such as audio and video,are routed to demultiplexer 125 from source interface 105. Demultiplexer125 separates the digital MPEG signal into individual data streams,e.g., audio and data streams. The MPEG signal contains several channels,which contain information to demultiplex the MPEG stream. Selector 110accesses information from the MPEG signal, as is known in the art, suchas the parsing of the header to determine the content in the stream.This is then used, via hardware logic or a microprocessor, to selectdesired channels to enable the signal to be demultiplexed. Thedemultiplexed digital signal streams are then transmitted to buffer 145.

Digital signals that are not in the same format as signals from encoder140 and demultiplexer 125 are routed to digital converter 120 forconversion to the appropriate digital format, e.g., MPEG or MPEG-2. Theconverted signal is then transmitted to buffer 145. Buffer 145 allows asingle data stream to be generated from signals arriving from varioussignal sources and processing devices. Signals arriving from encoder140, demultiplexer 125, and digital converter 120 can be transmitted toand stored in buffer 145 until the desired signals are all available.Buffer 145 would then transmit the signal to packetizer 150, based onsignals from selector 110.

Once all the selected analog and digital signals are in the same digitalformat, e.g., MPEG encoded, and are ready to be transmitted, packetizer150 processes each signal stream into packets for identification andlater retrieval. For example, each signal stream could include a headerhaving identifying information such as the original source and format,(e.g., type, resolution, aspect ratio) of the signal, audio content, andtime. Once the signals have been packetized, they are sent to formatter155, which multiplexes the signals onto a single digital transportstream 165. The transport stream can then be stored in digital storage160, such as an audio/video tape, a CD, a DVD, a hard disk drive, amemory stick, or a solid state memory device. An example of a portion ofa transport stream 165 is shown in FIG. 2. Packets 210, 215, 220, 225,and 230 were input to system 100 as a first analog NTSC signal, adigital MPEG-2 signal, an analog audio signal, a second analog NTSCsignal, and a digital data signal, respectively. Thus, if the first NTSCsignal, the digital MPEG-2 signal, and the analog audio signal wereinput to system 100 during overlapping time periods, all three signalscan be retrieved by accessing packets 210, 215, and 220 in the storedtransport stream 165.

Although the invention has been described with reference to particularembodiments, the description is only an example of the invention'sapplication and should not be taken as a limitation. Consequently,various adaptations and combinations of features of the embodimentsdisclosed are within the scope of the invention as defined by thefollowing claims.

1. A method for processing a plurality of signals, comprising: receivinga plurality of signals, having a plurality of different formats, at asingle source interface, wherein at least a first signal, a secondsignal and a third signal are received at said single source interface;routing the first signal, the second signal and the third signal fromthe single source interface to one or more selected devices; convertingthe first signal, routed from the single source interface, said firstsignal being an analog signal, to a desired format; converting thesecond signal, routed from the single source interface, said secondsignal being a digital signal, to the desired format; demultiplexing thethird signal in the desired format, said third signal having an audiocomponent and a video component; packetizing the first, second and thirdsignals; and multiplexing the first, second and third signals into asingle transport stream.
 2. The method according to claim 1, furthercomprising: storing the single transport stream.
 3. The method accordingto claim 1, further comprising buffering the first, second and thirdsignals prior to the packetizing.
 4. The method according to claim 1,wherein said converting the first signal comprises: demodulating theanalog signal; decoding the analog signal to a predetermined format;converting the analog signal in the predetermined format to a digitalsignal; and encoding the digital signal.
 5. The method according toclaim 4, wherein the desired format comprises an MPEG format.
 6. Themethod according to claim 1, further comprising a single selector toselect the first signal, the second signal and the third signal fromamong the plurality of signals.
 7. An apparatus for processing aplurality of signals comprising: a single source interface having one ormore input terminals to receive the plurality of signals having aplurality of different formats, wherein at least a first signal, asecond signal and a third signal are received at said single sourceinterface; a first converter to convert the first signal, said firstsignal being an analog signal among the plurality of signals, to adesired format; a second converter to convert the second signal, saidsecond signal being a digital signal among the plurality of signals, tothe desired format; a demultiplexer to demultiplex the third signal inthe desired format among the plurality of signals, said third signalhaving an audio component and a video component; a packetizer coupled tothe demultiplexer, and the first and second converters, said packetizerto packetize the first, second and third signals; and a formattercoupled to the packetizer, said formatter to multiplex the first, secondand third signals into a single transport stream.
 8. The apparatusaccording to claim 7, further comprising: a storage coupled to theformatter to store the single transport stream.
 9. The apparatusaccording to claim 7, further comprising: a selector coupled to thesingle source interface, the demultiplexer, and the first and secondconverters, said selector to select which of the plurality of signalsare sent to each of the demultiplexer and the first and secondconverters.
 10. The apparatus according to claim 7, further comprising:a buffer coupled between the first and second converters and thepacketizer.
 11. The apparatus according to claim 7, wherein the firstconverter comprises: a demodulator; a decoder coupled to thedemodulator; an analog-to-digital converter coupled to the demodulator;and an encoder coupled between the analog-to-digital converter and thepacketizer.
 12. The apparatus according to claim 11, wherein the encodercomprises an MPEG encoder.